In conjunction with a fuel cell-equipped vehicle, a technology for stopping the supply of a fuel gas and breaking an electrical connection if detecting a collision of the vehicle is known (e.g., see Japanese Patent Application Laid-Open Publication No. JP-A-2001-357863). Furthermore, in conjunction with an electric vehicle, a technology for shutting off a vehicle-driving electric power source without shutting off a control electric power source provided for electrical components, such as headlights and the like, if determining that it is impossible to avoid a collision is known (e.g., Japanese Patent Application Laid-Open Publication No JP-A-6-46502).
However, considering various fashions of collisions, the technology of Japanese Patent Application Laid-Open Publication No. JP-A-2001-357863, which performs actions after detecting a collision, needs contrivances in the vehicle body structure and the like for preventing degradation or breakage of the fuel cell, and therefore has a problem of increased cost and weight. Furthermore, although Japanese Patent Application Laid-Open Publication No. JP-A-6-46502 discloses a technology that predicts a collision of an electric vehicle and shuts off a vehicle-driving electric power source, the fuel-cell vehicles need to meet high-pressure gas handling standards in addition to the safety standards of electric vehicles.
From document EP 1 164 048 A2 are a method and apparatus for cutting off fuel supply of a fuel cell vehicle known, wherein the occurrence of degradation and damage to a fuel cell when power supply to accessories for driving the fuel cell is stopped, is prevented. Respective collision judgement sections read in an acceleration signal output from corresponding acceleration sensors and judge if the acceleration signal is greater than a predetermined first threshold acceleration, and if the judgement result is “YES”, close a hydrogen control valve. They then judge if the acceleration signal exceeds a predetermined second threshold acceleration greater than the first threshold acceleration, and if the judgement result is “YES”, stop power supply from a power storage unit to an air compressor for driving the fuel cell.
Another method for operating a pre-crash sensing system in a vehicle having a counter-measure system is known from US 2003/0076981 A1. The pre-crash system has a controller coupled to an object sensor. The object sensor has a vision system that includes image sensors to detect an impact in particular, a side impact. The image sensors provide a high frame rate to a video-processing chip which in turn is coupled to a general purpose controller. The general purpose controller determines whether an object is an impending threat and controls the deployment of an airbag through an airbag controller or other counter-measure. The high frame rate used in this pre-crash system allows not only a distance to the object but the velocity of the object is as well as the acceleration of the object to be determined and factored into the deployment decision.
Further, document WO 01/48847A discloses a fuel cell unit and a method for operating said unit, wherein a fuel cell unit that can be used in mobile objects, comprises an emergency stop. The device which is provided to execute an emergency stop cuts off the hydrogen supply and also initiates other measures as required, including decoupling and/or deactivation of the electricity and/or voltage transport devices.
A safety apparatus for a fuel cell vehicle is also known from JP 2001-189161 A. This apparatus comprises a fuel reformer, a sensor for detecting impact generated in an accident of a car, abnormal signal generating means for generating abnormal signals based on the output value of the sensor, valves for stopping the supplier of the fuel gas and oxidant gas based on the abnormal signal as a reformer-induction gas-stop means, an inert gas cylinder, cutoff valves being installed at front and rear of the reformer to fill the inert gas, and a value for introducing the inert gas based on the abnormal signal.
Further, document U.S. Pat. No. 5,816,358 discloses an electric vehicle with circuit breakers, wherein the electrically powered vehicle includes an electric motor connected to drive a wheel of the vehicle. The electric motor receives a supply of electric current from a power source; a power electronics device and superordinated controller regulate the current supply based upon signals received from a driver or operator of the vehicle. A sensor for sensing data indicative of an accident or impending accident is connected to the superordinated controller in which the sensor data is compared to predetermined limit values to determine if an accident situation exists. Upon determining that an accident situation exists, the superordinated controller activates a circuit breaker to disconnect the electric power supply and thereby interrupt the supply of electric current to the electric motor.